Audio playback unit



Jan. 24, 1967 E. J. GUsHuE ET A1. 3,300,591

AUDIO PLAYBACK UNIT med om. vso, 1963 v 4 Sheets-Sheet 2 i fiz ,1am/'g3 ----w N f INVENToR ATTORNEY5 mfr/a @A Jan. 24, 1967 E. J. GUSHUE ET AL 3,300,591

AUDIO PLAYBACK UNIT Filed oct. 3o, 1963 4 sheets-sheet s ATTORNEYS Jan. 24, 1967 E J, GUSHUE ET AL 3,300,591

AUDIO PLAYBACK UNIT 4 Sheets-Sheet 4 Filed OCT.. 50, 1963 NW wwN @n United States Patent O "a 3,300,591 AUDIO PLAYBACK UNIT Edward I. Gushue, Bedford Hills, and David A. Goldman, Yorktown Heights, N.Y., assignors to Coguitronics Corporation, Briarcliff Manor, N.Y., a corporation of New York Filed Gct. 30, 1963, Ser. No. 320,117 6 Claims. (Cl. 179--100.3)

This invention relates to an audio playback unit, and

more particularly to such a unit which has on photographic film a plurality of sound tracks containing optical signals representing messages which can be individually selected in any desired manner and played back in audible form.

1 As representative of the different types of equipment or environments in which such -a unit may be employed, there may be mentioned audio alarms, paging equipment, automatic test equipment, automatic audio programing functions, and digital to audio information readout functions, to name but a few.

It is an object of the present invention to provide an audio playback unit of the type above indicated, that is inexpensive and reliable in any of such environments.

Another object of this invention is to provide such an audio playback `unit which is simple in structure and operation, but which has an extremely long life and a zero wear factor on the storage of the messages, and in which there is no deterioration of playback with time yet high level playback signals are available.

Other objects and advantages of this invention will become apparent to those of ordinary skill in the art upon reading the appended claims and the following detailed description of the invention, in conjunction wit-h the drawings, in which:

FIGURE l is a diagrammatic representation of one embodiment of the invention,

FIGURE 2 is an elevational view, partially in crosssection, of a portion of FIGURE 1,

FIGURE 3 is .a plan view of a masking plate for use with another embodiment of the invention, Iand FIGURE 4, which consists of FIGURES 4A and 4B, is a detailed schematic circuit of a portion of FIGURE l.

In FIGURE l, a transparent or translucent rotatable drum 10 has its periphery covered with film 12 contain ing ten sound or information tracks 14 and one reference track 16. Each of the sound tracks contains optical variations or signals, for example as in any of the manners recorded in the sound track of motion picture films, and these optical signals represent predetermined messages. Though the specification proceeds as though each track contains .an independent message, it will be apparent to those skilled in the art that a lengthy message can utilize more than one tr-ack, when appropriate switching equipment is employed, for example as in the Hill Patent 2,969,525. With the presumption that each of the information or soundtracks 14 contains one full message in optical signal form, then reference track 16 contains one reference indication or mark 17 in optical form, which coincides with the end of each message on tracks 14, all messages preferably being arranged to end at the same angular point .around the drum. The reference mark may be utilized in various manners, as described below.

Consider FIGURE 2 for an insight to the structure of drum, etc. Drum 10 itself is comprised of the inner and outer end caps 13 and 15, each of which has a removable film retainer band 19, and the cylinder of film 12. At the center of each end cap is a suitable bearing 21 rotatable around a stationary post 18. This post is secured in base plate 23 in any suitable manner as shown.

3,300,591 Patented Jan. 24, 1967 ICC The end caps are preferably apertured for air circulation to keep temperature down and constant, whereby film buckling is prevented and the light sensors mentioned below are held at a better operating temperature.

For purposes of rotating drum 10, la gear 20 is secured externally to the inner end cap 13 around 'its bearing 21, that gear being driven by a toothed timing type belt 22, gear 24 and gear reduction motor 25. This causes the cylinder to rotate once every 54s second for example, with each track having an equ-al playback period.

To effect a playback from the photographic film tracks, a light source such 4as bulb 26 is mounted outside the rotating drum 10 and extends through the base plate 23 into a socket 27 that is connected to light switch 28 this switch and socket, along with motor capacitor 29 are mounted in a housing 31 which is flexibly secured by grommet 31a to b-ase plate 23. Also exteriorly of the drum, on a bracket supported .apertured base plate 30 extending the length of the drum closely adjacent its surface, are two separate elements 32 (only one shown) for defining a continuous light aperture extending the full length of the total track widths with a very narrow width, for example .0005 inch. Interiorly of the film cylinder 10 is a light sensor block holder 33 which is suitably secured to post 18 as by bolts through the upstanding tabs 33a. Holder 33 secures the light sensor block 34 which in turn has ten light sensitive cells 35 respectively for the sound tracks 14, plus one similar light sensitive cell 35a for the reference track 16.

As indicated in the illustrated embodiment, none of these cells or sensors require light shielding since in the ten track embodiment they are separated enough that they receive only the light coming through their respective tracks by which each is modulated. For the same drum length however, if a thirty-two track embodiment is effected, it is preferable to use the mask plate 37 of FIGURE 3. The light aperture width defining elements 32 are secured thereto via holes 39 and the assembly secured to base plate 30. Apertures 41 correspond in number to the number of film tracks and are separated the same amount, for example .070 inch on centers. In keeping with that example, they would be approximately .060 inch in diameter.

Though it is possible to reverse the relative positions of light bulb and sensors, such an arrangement is not by far as practical, economical, or convenient as the one here disclosed. With the lamp on the inside it would be much more difiicult to effect the necessary inside light aperture of .0005 inch at a close enough distance from the film. On the outside, the lamp, and film too, can be changed easier and the heat from the lamp dissipated without warping the lm. Maintenance in general is easier too. The light sensitive cells or sensors 35 and 35a are `optical transducers which convert the optical signals 011 the film into electrical signals; they may be tube type p-hotoelectric cells perhaps but preferably are solid state solar type cells which are light sensitive.

While drum 10 is rotating, the sensors 35 and 35a provide a continuous youtput on their respective output lines 36 and 38. As shown in FIGURE l, lines 36 are connected to a switching circuit 40 while the reference mark sensor output line 38 connects to an amplifier 42. Switching circu-it 40 and amplifier 42, along with amplifier 44 are shown in greater detail in FIGURE 4. From FIGURE 4 it is apparent that switching circuit 40 has not only the photoelectri-c or sensor inputs delivered to it, but also any one of ten different selection and switching signals respectively via the ten input terminals 46. These input terminals are collectively indicated in FIG- A URE l by line 48 which receives outputs from a selection matrix 50. This matrix in turn is controlled by a selection logic -circuit 52. In other w-ords, in a manner to be described, the selection matrix output signals on line 48 provide an enabling signal to just one vof the ten terminals 46 in switching circuit 40', at a time. In the FIGURE 4 circuitry, this causes the selected terminal 46 to be reduced to -12 volts for example, which in turn makes the connected transistor Q1 Q10 conductive. Normally, each of these transistors is held to a non-conducting state by the -il2 volts connected to line 54, which operates to bias the base of these transistors off, notwithstanding the -continuous input signals received thereby via lines 36, since terminals 46 are each normally at zero volts or ground level, for example.

When a given one of the transistors Q1 Q10 in FIGURE 4 is so selected and turned on, the light sensitive cell output signal connected thereto over line 36 is then transferred by that conductive transistor to amplifier 44 via coupling condenser 56 in output line 58.

Transistors Q11 16 and associated circuitry comprise amplifier 42 and effect an amplification onto output line 53 of the reference mark signals occurring on line 38. In a like manner, transistors Q17 20 comprise amplifier 44 and operate to amplify the information signals received from switching circuit 40 `over line 58. These amplified signals are transduced int-o audible form by a speaker 60.

In order to prevent hearing from the speaker any audible output such as noise which might otherwise occur from transients effected during the switching process, the output of transistor Q13 in the reference amplifier 42 is applied to its own amplifier 62, which includes transistor Q21, the output of which is applied via line 64 to the base of transistor Q20. Normally, transistor Q21 is held non-conductive by the base bias effected through resistor 66, but when the reference mark signal occurs in amplified form and is 'applied from trans-istor Q13 to the base of transistor Q21, the latter becomes conductive and effectively applies an A.C. ground signal to the base of transistor Q21. This turns transistor Q20 olf so that any transient si-gnal, which might otherwise be coupled from transistor Q19 through the volume control potentiometer 68 to transistor Q20, is suppressed during the switching operation. In other words the switching operation is .accomplished tacitly, i.e., without development of any switching transients into audible form.

It will be noted that the output of reference mark amplifier 42 yon line 56 lis applied to the selection logic circuit 52. This may be for either of two purposes one of which is to automatically update the logic by one so that conversion of the logic signals by matrix 50 causes the next `optical transducer output to be switched to amplifier 44. In other words, the selection logic 52 may be a stepping switch or the like which can operate through matrix 50, or directly to the input terminals 46 of switching circuit 40, to effect sequential and continuous operation `of the circuit, whereby the messages on the ten different tracks 14 are readout one after the other in a predetermined sequence. Another and alternative use of the reference mark signal delivered by line 56 to the selection logic circuit 52 is to employ that signal just as a has read or timing signal whereby the selection logic circuit is notified that a newly selected logic can now be readout to matrix 50 when otherwise desired of course, this employment of the reference mark signal is also present in :the above mentioned updating use thereof. The selection logic circuit may be `of any desired type, which generates its own signals internally, or receives them externally, as required for the particular situation in which the equipment is being employed.

The suppression signal on line 64 may last for 50* milliseconds for example, in order to allot a desired amount of time for the selection logic, matrix, and switch 40 to select and switch in another track.

Matrix 50 can be of any type required to effect the desired conversion. For example, if the selection logic circuit 52 applies to the matrix a live bit binary signal, then it is necessary for the matrix to convert this into a one-out-of-ten type signal for terminals 46 in :the switching circuit. On the other hand, the input to matrix 50 may be a decimal input, or it may be a one-'out-of-N where N is the number of information tracks on the drum. Matrices to provide any desired arrangement are wellknown in the art.

Notwithstanding the fact that the foregoing description has designated the number -of linformation tracks at ten, it is appreciated that the number of information tracks may be more or less. Furthermore, multiple units can be interconnected to expand the available audio vocabulary, and the motor 24 may have a clutch-actuated drive for zero access time for message playback. Preferably, solid state electronics is employed throughout, but other type of electronics may be utilized as desired. As an example, the playback frequency response may be in the l0 to 4000 c.p.s. range.

From the foregoing description, it is apparent this invention has provided audio playback equipment having the advantages and accomplishing the objects indicated. An embodiment of lthe invention may be constructed in relatively miniaturized `form or as large as desired. With the versatility available by means of the numerous types of messages which may 'be placed in the sound tracks, the invention conveniently lends itself to employment in a large variety of situations in all of which operation may be accomplished automatically or manually as desired.

Other objects and advantages, and even further modifications of the invention, will rbecome apparent to those of ordinary skill in the art upon reading this disclosure. However, it is to Ibe 'understood that this disclosure is illustrative -of the invention, and not limitative thereof, the invention being defined by the appended claims.

What is claimed is:

1. Audio playback equipment comprising:

a film cylinder having fixed around its periphery a plurality of sound tracks containing optical signals representing audio messages capable of being transA duced into audible form, each of said optical signal messages ending at a predetermined point on its associated track,

means for developing an electrical reference signal indicating the end of said sound tracks,

means for rotating said cylinder and 'thereby rotating all said tracks simultaneously,

means including a plurality of stationary optical transducers respectively disposed adjacent said tracks, for providing, during rotationv lof said cylinder in the same direction, simultaneously occurring, respective outputs representing a conversion of said optical signals into electrical sound signals,

means for amplifying said electrical `,sound signals,

means for transducing said amplified electrical sound signals into audible messages, and

automatic means using said electrical reference signal and including a switching circuit for selecting any -desired one of said simultaneously occurring optical transducer outputs while said cylinder is rotating in said same direction and when `said switching circuit is operatively associated with one of said message ending points and tacitly switching the corresponding electrical sound signals t-o said amplifying means for playback in audio form by said transducing means.

2. Audi-o playback equipment comprising:

a film cylinder having fixed around its periphery a plurality of sound tracks containing optical signals representing audio messages capable of being transduced into audible form, each of said optical signal messages ending at a predetermined point on its associated tracks,

means for rotating said cylinder and thereby rotating all said tracks simultaneously,

means including a plurality of stationary optical transducers respectively disposed adjacent said tracks, for providing, during rotation of said cylinder in the same direction, simultaneously occurring respective outputs representing a conversion of said optical signals into electrical signals,

means for amplifying said electrical signals,

means for transducing said amplified electrical signals into audible messages,

automatic means including a switching circuit for selecting any one of said simultaneously occurring optical transducer outputs while said cylinder is rotating in said same direction and when said switching circuit is operatively associated with one of said message ending points and switching the corresponding electrical signals to said amplifying means for playback in audio lform by said transducing means, and

means for suppressing the operation of said amplifying means While said switching circuit is operative to switch the selected electrical signals to the amplifying means as aforesaid.

3. Audio playback equipment as in claim 2 wherein said reference signal means includes:

a reference track on said lm Icylinder for indicating the end of each optical signal message in the said sound tracks, and said automatic means includes means for delivering a suppressing signal to said amplifying means upon sensing Isuch indications.

4. Audio playback equipment as in claim 3 including means for coupling the sensed reference indication signals to said selecting means for indicating thereto that another one of said optical transducer outputs may then be selected.

5. Equipment as in claim 4 wherein said selecting means includes a selection matrix for operating said switching circuit and a selection logic circuit for operating said selection matrix.

6. Audio playback equipment comprising:

a lm cylinder having fixed around its periphery a plurality of sound tracks containing optical signals representing audio messages capable of being transduced into audible form,

said lm cylinder having a xed reference track containing at least one reference mark for indicating the end of said sound tracks,

means for rotating said cylinder and all said tracks simultaneously,

means including a stationary light source on the outside of said cylinder and each of said tracks and on the inside thereof a plurality of stationary optical transducers respectively disposed adjacent each of said sound and reference tracks for providing, during rotation of said cylinder, simultaneously `occurring outputs representing conversion of said optical message signals and reference mark into respective electrical signals,

CTI

nals,

means including a speaker for transducing said arnpliiied message signals into audible messages,

second means for amplifying said electrical reference 10 signals,

a switching circuit for continuously receiving the said simultaneously occurring outputs from the optical transducers associated with the said sound tracks and switching a selected one thereof to the said rst amplifying means for playback in audio form by said transducing means,

means connecting an output of said second amplifying l means to said rst amplifying means for suppressing the output of said first amplifying means during said 2n switching,

an input selection logic ycircuit coupled to an output of said second amplifying means and operated thereby to allow an output signal representing the `selection of another one of said optical transducer outputs,

and

a selection matrix for converting the said output signal of said selection logic circuit to an input suitable for said switching circuit for causing the desired selection in the switching circuit of the instant one of said information optical transducer out-puts desired.

References Cited by the Examiner UNITED STATES PATENTS 2,142,391 1/1939 Fuschi 179-100.3 2,463,534 3/1949 Hawkins 179-100.3 2,507,432 5/1950 Bass 330-130 2,670,212 2/1954 Heller 179-100.2 2,975,672 3/ 1961 Shields 179-100.2

3,109,898 11/1963 Gray 179-100.2

Assistant Examiners.

rst means for amplifying said electrical message sig- 

1. AUDIO PLAYBACK EQUIPMENT COMPRISING: A FILM CYLINDER HAVING FIXED AROUND ITS PERIPHERY A PLURALITY OF SOUND TRACKS CONTAINING OPTICAL SIGNALS REPRESENTING AUDIO MESSAGES CAPABLE OF BEING TRANSDUCED INTO AUDIBLE FORM, EACH OF SAID OPTICAL SIGNAL MESSAGES ENDING AT A PREDETERMINED POINT ON ITS ASSOCIATED TRACK, MEANS FOR DEVELOPING AN ELECTRICAL REFERENCE SIGNAL INDICATING THE END OF SAID SOUND TRACKS, MEANS FOR ROTATING SAID CYLINDER AND THEREBY ROTATING ALL SAID TRACKS SIMULTANEOUSLY, MEANS INCLUDING A PLURALITY OF STATIONARY OPTICAL TRANSDUCERS RESPECTIVELY DISPOSED ADJACENT SAID TRACKS, FOR PROVIDING, DURING ROTATION OF SAID CYLINDER IN THE SAME DIRECTION, SIMULTANEOUSLY OCCURRING, RESPECTIVE OUTPUTS REPRESENTING A CONVERSION OF SAID OPTICAL SIGNALS INTO ELECTRICAL SOUND SIGNALS, MEANS FOR AMPLIFYING SAID ELECTRICAL SOUND SIGNALS, MEANS FOR TRANSDUCING SAID AMPLIFIED ELECTRICAL SOUND SIGNALS INTO AUDIBLE MESSAGES, AND AUTOMATIC MEANS USING SAID ELECTRICAL REFERENCE SIGNAL AND INCLUDING A SWITCHING CIRCUIT FOR SELECTING ANY DESIRED ONE OF SAID SIMULTANEOUSLY OCCURRING OPTICAL TRANSDUCER OUTPUTS WHILE SAID CYLINDER IS ROTATING IN SAID SAME DIRECTION AND WHEN SAID SWITCHING CIRCUIT OPERATIVELY ASSOCIATED WITH ONE END OF SAID MESSAGE ENDING POINTS AND TACITLY SWITCHING THE CORRESPONDING ELECTRICAL SOUND SIGNALS TO SAID AMPLIFYING MEANS FOR PLAYBACK IN AUDIO FORM BY SAID TRANSDUCING MEANS. 